The Effects of Reduction of Feeding Space on the Behaviour of Captive Starlings Sturnus vulgaris

Eleven captive starlings were given food in troughs. Various parameters of the birds' behaviour were measured when trough length, equivalent to feeding space, was reduced. Restriction of feeding space increased the number of agonistic encounters between feeding birds but did not affect their feeding rates or the total amount of food they took. A dominance hierarchy was established in the flock, in which dominant birds had higher feeding rates and initiated more agonistic encounters than subordinates. All individuals had higher feeding rates when feeding with others than when feeding alone. A stepwise multiple regression analysis showed that the main factors that influenced an individual's feeding rate were the feeding rate of its nearest neighbour and the number of birds feeding at the trough. However, although starlings preferred to feed socially, their behaviour at the feeding trough was highly individualistic, as indicated by the various combinations of factors influencing feeding rates.